1. Technical Field
The present invention relates in general to a charge control method and a computer, and in particular to a charge control method for controlling the charge of a plurality of batteries and a computer which employs the charge control method.
2. Description of the Related Art
Recently, with the spread of mobile computing, portable personal computers which vary in size and function (hereinafter referred to as xe2x80x9cportable PCsxe2x80x9d) have been developed. For example, typical portable PCs include notebook personal computers (PCs), subnotebook PCs, palmtop PCs, and personal data assistants (PDAs).
A portable PC has a battery contained in its body. Such a built-in battery allows the user to use the portable PC under circumstances where no commercial electric power is available, for example, in a train. A battery which can be operated many times by recharging is commonly used as a built-in battery.
Under circumstances wherein commercial electric power is available, the user connects the portable PC to an AC adapter (a device which accepts a commercial alternating current (AC) and provides a direct current). This allows desired computing operations to be performed and at the same time, the battery built in the portable PC can be charged.
A single battery has a limited capacity and thus the operating time of a portable PC is also limited. In order to increase the operating time of the portable PC, two batteries may be contained in the portable PC. These two batteries are referred to as the main battery and the second battery, respectively. First, the portable PC starts to operate on the second battery. When the second battery runs down, the portable PC can continue to operate on the main battery instead of the second battery.
In general, a charger has the capability of charging only a single battery at a time and if two batteries must be charged, the main battery is first charged and then the second battery is charged.
A charge control method by which batteries can be efficiently charged, even if the charging is aborted, as well as a computer which employs such a charge control method is provided. The charge to the main battery is started and then the charge to the main battery is stopped when the amount of electric energy in the main battery reaches a predetermined value (steps 200 to 204).
Next, the charge to the second battery is started and then the charge to the second battery is stopped when the amount of electric energy in the second battery reaches a predetermined value (steps 206 to 210). Next, the charge to the main battery is restarted and then the charge to the main battery is stopped when the amount of electric energy in the main battery reaches 100%. Thereafter, the charge to the second battery is restarted and then the charge to the secondary battery is stopped when the amount of electric energy in the second battery reaches 100% (steps 212 to 222).
All objects, features, and advantages of the present invention will become apparent in the following detailed written description.